Grasses can be classified as sod-formers, or bunch grasses, cool season, or warm season and native or introduced. Sod-forming grasses reproduce from their root systems as well as from seeds. Bunch grasses grow in bunches and reproduce primarily from seeds. Cool-season grasses actively grow during the cool months of the year, in the spring and the fall; warm season grasses actively grow during the summer months. Native grasses are those species of grass that are historically found in this area. Introduced grasses are those that are from a different area.
There are several predetermined factors that must be considered when selecting a grass. Predetermined factors such as soil, climate and available water are factors that you must plan around. Soil texture dictates what type of grass will perform the best on a given site. As a rule of thumb, short, sod-forming grasses perform best on the heavy soils such as clay, and tall grasses perform best on the lighter sandy soils.
In this low rainfall area, a loamy textured soil, which is a combination of the three different soil particles: clay, silt and sand, can grow both mid-grasses and short grasses, but not tall grasses with- out sufficient water.
Our front-range climate typically gives us 12 to 14 inches of total precipitation annually, and we have an average annual growing season of 120-150 days per year. The amount of available water received each year from annual precipitation is certainly enough to support many of the native grass species in this area. However, if you decide that an introduced grass species would better suit your needs, and you do not have irrigation water available, verify that it is a grass adapted to your soils, climate and water regime prior to planting.
Function for your situation should be considered next. Several different seeding recommendations are listed in the tables below. There are mixes for pasture areas, outlying lawn/recreation areas and wildlife areas. If you do not see a mix listed below that fits your situation, or you are unsure of your soil type, please call your local NRCS office for a site-specific recommendation, especially if you suspect a high salt content in your soil.
Preparing the Seedbed
The best seedbed for all situations is one that is free of debris including old weed matter, weed seed, rocks, clods, and other impervious material. A good seedbed should also be fluffy yet firm. A test of the perfect seedbed is to take a walk across it. You should not stumble over old weed matter or dirt clods, and your footprints should sink about ¼” into the soil. Sometimes it will take several mechanical operations to obtain the perfect seedbed. Those operations can include deep ripping to a depth of 18″ if severe compaction exists. This would then be followed by a disc operation to breakup the bigger clods. At this point a second disc operation or a harrow operation would be needed to breakup the smaller clods and smooth the surface. Are you ready to plant the grass now? The answer is yes, if your site is on heavy soil that did not previously have an abundance of weed cover. However, if your soil is lighter than a loam and/or had a previously abundant weed cover, then it is strongly recommended that before you plant your grass, a cover crop is established to protect the seedbed, and discourage annual weed growth.
There are several types of cover crops that can be used. One of those is a hybrid sterile sorghum cover crop. Start by preparing the seedbed as listed above in the spring around early May. Drill the sorghum at a rate of 4 to 8 pounds to the acre on clay or loam soils, and 6 to 10 pounds to the acre on sandy soils. Seeding depth is 1″, and row spacing is 14″ to 21″ apart, the closer the spacing the less weed competition. Planting dates are between mid-May to mid-June. This cover crop will germinate and begin to grow within 7 to 12 days. Typically, the cover crop will outgrow and out-compete annual invasive weeds over the summer. If significant growth is achieved on the cover crop, mowing may be necessary. Ideally, the stubble left after mowing should be 12″ to 14″. Any mowing equipment that does not produce a windrow of residue can be used. If all of the weeds have been terminated, and you have just the standing sorghum stubble in the field, you are now ready to plant your grass! The grass can be seeded directly into the standing sorghum stubble with a good grass drill.
Seeding the Grass
Dryland grass seeding can be done between November 15th and April 30th on unfrozen ground. Seeding depth is ¼” to ¾”.
Irrigated grass seeding can be done between November 15th and June 30th on unfrozen ground. Seeding depth is also ¼” to ¾”.
In both cases, the recommended machine to seed to grass is a grass drill. A good grass drill should be equipped with the following parts:
- An agitator in the seedbox-allows for equal distribution of seed.
- Double disc furrow openers-opens a small trench for the seed
- Drop tube placement-situated between the double disc furrow openers.
- Depth bands-control the depth of the planting.
- Press wheels or a drag chain-will cover and firm the soil around the seed, ensuring good seed to soil contact.
- Machinery should be set up for a row spacing of 7″ to 12″.
If the area you have to seed is small and you wish to apply the seed with a hand broadcaster or another broadcast method, be sure to double the seeding rates as listed above. The area should then be raked and packed to ensure good seed to soil contact.
Seed Mixes (PDF)
Small Acreage Grass Seeding Spreadsheets
Follow-up Weed Control
The most important factor in establishing grass after it is seeded is continued weed control. Timely mowing operations are the most successful. Mowing annual invasive weeds immediately prior to those weeds setting seed is the most effective time to mow. Mowing may be necessary several times the first growing season. Mowing may also be necessary in the second and third growing years.
If you need help in weed identification and determining when to mow, please call your local NRCS or Extension office.
If perennial invasive or noxious weeds exist, spot chemical control might be the most effective weed control measures. Be sure to consult with a local licensed chemical representative for specific recommendations.